Hippocampal mechanisms of social learning in animal models of autism

The causes of social dysfunction in autism, a core symptom of the disorder, remain unknown. Many genetic abnormalities seem to be involved in the disorder. Because behavioral problems are mediated by malfunctions in neural circuits, it is likely that diverse genetic defects converge to cause similar functional abnormalities at the neural circuit level. Therefore, understanding the neural circuit malfunctions may hold the key to understanding social dysfunction in autism.

The neural circuits involved in normal social behavior have not yet been identified, however. Daoyun Ji and his colleagues at Baylor College of Medicine in Houston, Texas, are studying which brain areas are involved in a particular type of social behavior called observational learning, whereby one learns by observing others’ actions. The researchers plan to test the hypothesis that neural circuits in the hippocampus are involved in observational learning.

Ji’s team plans to use large-scale multi-electrode arrays to record activity from a large number of hippocampal neurons of freely moving rats while they are engaged in observational tasks. After determining hippocampal responses to observation in normal rats, the researchers plan to study how the responses are altered in rats lacking MeCP2 and PTEN — two genes implicated in autism spectrum disorders.

The study may reveal a novel neural circuit mechanism involved in social learning, and possible circuit malfunctions related to the social difficulties of autism. The results may lead to novel intervention strategies that target neural circuit malfunctions without treating individual molecular defects.